The present invention relates to a throttle valve position controlling apparatus for an engine and a slip controlling apparatus, and more particularly, to a throttle valve position controlling apparatus and a slip controlling apparatus which does not use any throttle valve position sensor to detect the opening degree of the throttle valve.
The opening degree of the throttle valve of the engine is adjusted in correspondence to the amount of actuating of the accelerator pedal; however, it is necessary to adjust the valve opening degree without actuation of the accelerator pedal during idling, for example. Therefore, there exists a throttle valve which can be driven by a motor as well. Further, there also exists a tandem throttle valve which has a sub throttle valve whose opening degree is adjusted by a motor, in addition to a main throttle valve, the opening degree of which is adjusted by the accelerator pedal.
In order to exactly control the valve opening degree with use of a motor, a throttle valve position sensor is required which serves to detect the valve opening degree or the valve position exactly. There are two types of throttle valve position sensors, that is, contact type and non-contact type. The contact type throttle valve position sensor has a disadvantage that the component part suffers abrasion. In particular, since the throttle valve driven by the motor is used frequently at the opening degrees around its full-closed position, abrasion is notable in the vicinity of the full-closed position. Abrasion of the throttle valve position sensor hinders the detection of the throttle valve position from being effected exactly, thereby making it impossible to control the engine correctly. In order to avoid this disadvantage, it is possible to use a non-contact type throttle valve position sensor However, the non-contact type throttle valve position sensor is expensive.